The utilization of in vitro cultured cells in research, medicine, bioprocessing, and bioproduction settings is expanding exponentially. While widely applied and often viewed as common practice, cell culture is a highly variable and dynamic process which has significant impact on the overall quality and performance of the culture. The nuances of cell culture are often addressed with simple procedural or pattern alterations in a laboratory setting, yet these alterations are more often than not incompatible with scale up for successful batch culture of cells in bioprocessing settings.
Mass culture of cellular systems is utilized in settings ranging from drug discovery to bioproduction of therapeutic antibodies to development of new therapeutics and vaccines utilizing cultured cells (cell therapy) to the manufacture of new tissues (tissue engineering). All of these processes require a large number of cells in a similar state thereby requiring mass production and utilization (bioprocessing).
Mass production and utilization of cell media offers a number of technical challenges starting with the simple fact that cell culture is typically characterized by low growth and production rates in comparison with chemical processes. Given the inherent challenges associated with cell culture, processes have evolved to create optimal conditions to maintain cell physiological performance during ex vivo cultivation. In essence, these efforts have been directed at controlling various process parameters to reduce physical and chemical stress, provide proper nutrition to support cell growth and function, reduce bio-waste and toxin accumulation. These efforts have been focused on increasing production, reducing apoptosis, maintaining reproducibility and stability, and maximizing cell culture efficacy.
While cellular bioprocessing has become integral in basic and applied research, as well as in medical therapeutics, a number of significant obstacles have resulted from the stresses created by the conditions used to support proper cell growth and function in an in vitro environment. Alterations in temperature, physical manipulation, pH, osmolality, oxygen and carbon dioxide levels, nutrient levels, chemical stress, waste accumulation, cell interactions and signaling have a significant effect on culture growth and performance. Given the influence of these and other stressors on overall bioproduction efficacy, several approaches to controlling cell culture have evolved including custom and specialized media and bioreactors (culture container) and monitoring engineering. In the area of bioreactors, tremendous effort has been dedicated to the development of devices, containers, pumps, and monitoring sensors in an effort to reduce the variation in the culture conditions, thereby creating a controlled and sustainable environment.
An increased amount of recent activity in culture media formulation has renewed efforts in the biotechnology industry to develop improved culture media formulations to increase product yield while reducing cost. The renewal of these efforts has been spurred on by the recognition that classical culture media developed in the past were primarily designed for simple small scale culture and have proved to be only partially compatible with large scale procedure. As such, much of the classical cell culture media formulation fundamentals fall short in providing a means to support efficient cell bioprocessing. In this regard, challenges remain to develop a specialized culture media that can be customized to individual cell types and culture production processes, procedures and protocols, and the individual response of cells to variances in each of the other parameters associated with cell culture.
Further, in the field of medical diagnostics, including stem cell therapy and cancer, a challenge exists to eliminate or select one or more cell types from a mixed population of cancerous and non-tumorigenic cells without the use of fluorescent tags, chemotherapeutic agents or antibodies. Indeed, cancer stem cells are thought to be present in less than 1% of a stem cell population and antibodies are currently used to purify them.
The use of human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs) for cell therapy will ultimately require selective, non-invasive elimination of the small number of tumorigenic undifferentiated cells known to be present in these populations. While the use of cytotoxic monoclonal antibodies and other transfection systems are currently being developed to address this problem, neither are consistent with FDA regulations for cell therapy. Also, the ability to selectively eliminate cancer cells in a cell culture setting using mutagenic, chemotherapeutic compounds is the basis of cancer drug discovery; but this approach typically requires the use of DNA binding drugs and/or tumor suppressor activators that cannot be used in any procedure that ultimately results in the transfusion of cell products into patients.
A need exists to address this complex issue of media formulation and development and on improving cell culture used in bioprocessing. Bioprocessing needs to be improved and standardized by focusing on all the components of the process including collection, processing, manipulation, culture and selection. Further, bioprocessing must be able to properly maintain cell and tissue specimens such that in their subsequent use or analysis, they retain the characteristics of the system equivalent to their native in vivo state. The impact and importance of these bioprocessing needs will affect the future of medicine.
In addition, a need exists to inhibit cell stress pathways in normal primary cells and tumorigenic cells to either completely eliminate or select the targeted cell type based on the stress pathway inhibitor used. The approach could desirably be used for a variety of applications where the non-chemical/antibody selection of a desired cell phenotype is required such that the product could be used in stem cell therapy, regenerative medicine, cell diagnostics and cancer treatment. A portfolio of therapeutic agents will beneficially be designed for the non-invasive selection and/or elimination of targeted cell types.
The following invention will address the current needs in the industry of bioprocessing and targeted cell selection. The technology bridges the gap between current cell culture technologies (media and devices) and that of the ever-growing demand for increased culture efficiency. Desirably, these improvements will supplement and improve cells undergoing bioprocessing such as in harvesting, bulk culture, fluorescence activated cell sorting (FACS), shipping, transfection and protein bioproduction, advantageously impacting research and medicine overall.